<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /* 背景样式用于设置 背景颜色 图片相关内容 */
        
        body {
            /* 0无需任何单位 */
            margin: 0;
            /* 默认由内容撑起 */
        }
        
        div {
            background-color: aqua;
            /* 宽度可以直接设置为100%为当前页面宽度(百分百单位为父元素大小的百分百) */
            width: 100%;
            /* vw vh叫做视口宽度与视口(页面可视大小)高度 */
            height: 100vh;
        }
        
        .d1 {
            background-image: url(../img/yld.gif);
            background-size: 100%;
            background-repeat: no-repeat;
            background-position: center;
            background-attachment: fixed;
        }
        
        .d2 {
            background: yellow url(../img/kn.gif) no-repeat center fixed;
            background-size: 100%;
        }
        
        .d3 {
            background: yellow url(../img/gz.gif) no-repeat center fixed;
            background-size: 100%;
        }
        
        .d4 {
            background: yellow url(../img/dz2.gif) no-repeat center fixed;
            background-size: 100%;
        }
        
        .d5 {
            background: yellow url(../img/dz.gif) no-repeat center fixed;
            background-size: 100%;
        }
    </style>
</head>

<body>
    <div class="d1"></div>
    <div class="d2"></div>
    <div class="d3"></div>
    <div class="d4"></div>
    <div class="d5"></div>
</body>

</html>